Owing to their excellent flexibility and hygiene property, the thermoplastic resins have heretofore been widely used as packing materials. The thermoplastic resins, however, permit gases such as oxygen and carbonic acid gas to permeate through to a large extent causing, therefore, the containers made from the thermoplastic resins to be incapable of storing foods for extended periods of time.
To compensate for such a defect of the thermoplastic resins, therefore, there have been proposed a variety of multilayered formed bodies combining the layers of the thermoplastic resins with a layer of a barrier resin such as ethylene-vinyl alcohol copolymer or the like. Depending on the form and the method of producing the formed bodies of the multilayered structure, however, it becomes necessary to install new facilities or to increase the number of the forming steps resulting, however, in an increase in the cost of production and without still satisfying the requirements in regard to productivity and economy.
There have also been known resin compositions obtained by blending the thermoplastic resins with barrier resins such as ethylene-vinyl alcohol copolymer and the like. For instance, the following patent documents 1 and 2 are proposing multilayered hollow containers provided with a barrier layer of a resin composition that comprises a polyolefin resin and an ethylene-vinyl alcohol copolymer.